1. Field of the Invention
Factor VIIIC is a plasma protein that participates in the intrinsic pathway of blood coagulation. It is absent or defective in individuals with the hereditary X chromosome-linked recessive bleeding disorder hemophilia A. Great difficulty has been encountered in isolating Factor VIIIC due to its extremely low concentration in plasma and the fact that it appears to be an intermediate or final degradation product of a larger protein precursor. Therefore, efforts to isolate Factor VIIIC have led to complex mixtures of significant heterogeneity and varying molecular weights.
One of the approaches which has found broad application to the production of physiologically active proteins involves the isolation of the protein of interest in purified form. The protein of interest provides invaluable aids in the development of a recombinant DNA capability for the production of the protein. By having the protein of interest, one may prepare monoclonal antibodies which are specific for the protein and can be used to establish the production of the protein in lysates, expression from messenger RNA in oocytes, or from a cDNA gene in unicellular microorganisms. In addition, by amino acid sequencing, one can develop probes, employing codons coding for the particular amino acid sequence, for hybridization to messenger RNA, chromosomal DNA or cDNA and, therefore, provide for the detection, isolation and expression of the relevant gene or message and the production of the desired product in high yield in one or more hosts.
2. Description of the Prior Art
U.S. Pat. No. 4,361,509 and references cited therein describe purification of Factor VIIIC. See also Fulcher and Zimmerman, Proc. Natl. Acad. Sci. USA (1982) 79:1648-1652. Tuddenham et al., J. of Lab. Clinical Medicine (1979) 93:40-53 describes purification of Factor VIIIC using polyclonal antibodies. Austen, British J. Hematology (1979) 43:669-674 describes the use of aminohexyl-Sepharose for Factor VIIIC purification. Weinstein et al., Proc. Natl. Acad. Sci. USA (1981) 78:5137-5141 describes a study of the effect of thrombin on Factor VIIIC. See also Kuo et al., Abstracts for IX International Congress of Thrombosis and Hemostasis, (Copenhagen; July, 1983).